Laryngeal and Tracheal Stenosis

Image: Normal laryngeal and tracheal anatomy

The larynx

The larynx is a structure composed primarily of cartilage, muscle, and other soft tissues. It sits above the trachea (windpipe), and plays an important role in a child’s ability to breathe, speak, and swallow. The larynx has three main parts: the supraglottis, glottis and subglottis. The supraglottis is the part of the larynx that is above the vocal cords. The glottis is another term for the vocal cords (also called vocal folds). The subglottis is the area just below the vocal cords, and it is unique because it is made up of the only complete ring of cartilage that normally occurs in the airway. Each location in the larynx has the ability to become injured. 

The trachea

The trachea, or windpipe, is composed of incomplete rings of cartilage that are shaped like horseshoes that line the roof of the airway. The floor of the windpipe is made up of a band of muscle and soft tissue. The trachea has the ability to expand and contract when we breathe, and injury to the trachea may include scarring or narrowing of the airway (stenosis).

Airway stenosis

Stenosis is a term used to describe a narrowing of the airway. Stenosis can occur in any of the three parts of the larynx, or in the trachea itself. If the narrowing is severe, it can affect a child’s ability to breathe and cough up secretions. Airway stenosis can also affect the voice, the ability to swallow, and can make mild cold symptoms much more severe. 

Stenosis of the larynx or trachea in children can be present at birth in a small proportion of children. This is called “congenital” airway stenosis. More commonly, narrowing or stenosis of the airway occurs after an injury to the airway. The most common kind of airway injury occurs in newborn patients who require intubation (the placement of a breathing tube) after birth. This is more common in children who are born prematurely and require a mechanical ventilator while their lungs develop. Although this form of mechanical ventilation is lifesaving in the premature child, it also has the risk of causing airway scarring that leads to airway narrowing. The subglottis (area immediately below the vocal cords) is the most likely site of airway narrowing due to prolonged intubation. This is commonly referred to as Subglottic Stenosis. 

How is airway stenosis diagnosed?

Diagnosis of airway narrowing (stenosis) requires a visit with a Ear Nose and Throat specialist (Otolaryngologist) for a thorough physical examination, and an endoscopic evaluation of the airway. Children with airway stenosis may have symptoms including the inability to cough up secretions, severe shortness of breath, noisy breathing, difficulty eating, or recurrent croup-like infections at a frequency or age that is not typical. Other times, children with airway stenosis may have no symptoms. Premature infants with airway stenosis are frequently diagnosed only after the breathing tube is removed and they are unable to breathe adequately on their own. In children with a suspicion for airway stenosis, a microlaryngoscopy and bronchoscopy are performed. This involves using a microscope and camera to look at the larynx and the trachea, identifying and measuring the airway narrowing, with the child under anesthesia in the operating room.

How is airway stenosis treated?

Treatment of airway stenosis depends on the location and the severity of narrowing. If mild, treatment may only include observation. If severe, endoscopic interventions or surgical reconstruction of the airway may be required.

Endoscopic interventions

Endoscopic interventions are performed through the mouth, and do not require any incisions on the skin. Several endoscopic interventions have been designed to treat children with airway obstruction. Some of these include balloon dilation, endoscopic cricoid split procedures, and endoscopic posterior cartilage grafting procedures.

• Balloon dilation involves inserting a special surgical balloon into the airway at the location of narrowing. The balloon is then inflated, expanding the area of narrowing. Balloon dilation is performed in the operating room under general anesthesia, is often performed multiple times in the treatment of airway stenosis, and may be used in combination with other procedures.
• Endoscopic cricoid split involves making an incision in the ring of cartilage below the vocal cords (cricoid ring), allowing for the ring of cartilage to be expanded. This procedure is performed in the operating room under general anesthesia, and may be performed in combination with other procedures.
• Endoscopic posterior cartilage grafting involves making an incision in the back of the cartilage ring just below the vocal cords (cricoid ring), and placing a piece of rib cartilage into the incision. This procedure permanently widens the airway at this location, and may be performed for laryngeal stenosis or bilateral vocal cord paralysis. This procedure is performed in the operating room under general anesthesia.

Open interventions

Open interventions are performed through an incision in the neck. This incision usually heals very well, and can often be incorporated into the patient’s tracheostomy stoma if one exists. These open surgical procedures designed to treat airway stenosis are often called “laryngotracheoplasty (LTP)” or “laryngotracheal reconstruction (LTR)”, and encompass a wide variety of different techniques. It is important to remember that not all surgical procedures are appropriate for every child. Each procedure has its own set of risks and benefits, and should be carefully selected only after a comprehensive evaluation with a pediatric Ear Nose and Throat specialist (Otolaryngologist).

Specific airway reconstruction procedures

The primary goal of airway reconstruction is to widen the location of narrowing. There are three main categories of airway reconstruction designed to achieve this:

• Expansion laryngoplasty: Airway expansion and grafting procedure that involves making an incision in the front and/or back of the airway, expanding the narrow segment, and placing rib cartilage in the area of expansion.
• Tracheal resection: Procedure that involves removing the segment of narrow trachea, and sewing together the cut ends of normal trachea. This is often performed for tracheal narrowing rather than subglottic narrowing. When the subglottis or a component of the subglottis is involved, the procedure performed is a modified version of tracheal resection called a “cricotracheal resection (CTR).”
• Slide tracheoplasty: Procedure that involves dividing the trachea at the area of narrowing, then opening the back and the front of each segment of airway at the location of stenosis. The bottom portion of the airway is then slid on top of the upper portion of the airway, allowing for a wider airway to be created when the two tracheal segments are sewn together. When the stenosis is in the top half of the trachea, the procedure is called a “cervical” slide tracheoplasty. Slide tracheoplasty is also frequently performed for tracheal stenosis that is further down the airway under the sternum (breastbone).

Single stage vs. double stage airway reconstruction

Airway reconstruction is often performed in a patient who has a tracheostomy in place. A single stage procedure refers to an airway reconstruction technique that is performed at the same time that the tracheostomy tube is removed. This is often performed for less-severe stenosis, but may be performed for patients with severe stenosis under select circumstances.

A double-stage procedure refers to an airway reconstruction that is performed and allowed to heal completely before removal of the tracheostomy tube. This is frequently performed for more severe stenosis, or in revision airway reconstruction.